Array Substrate TFT Doping Layout for Self-Heating Stability

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Solution Overview

Problem

Transistors with high mobility suffer from poor stability in operation.

Innovation Solution

An array substrate design that includes a first transistor with a specific doping structure, where the second doped sub-portion has a lower ion doping concentration than the first doped sub-portion, reducing voltage drop and improving stability by increasing resistance, thereby addressing self-heating issues.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If transistors with high mobility are used, then performance is improved, but stability deteriorates due to self-heating

Engineering Contradiction:
Improvetransistor performanceVSAvoidtransistor stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies local quality by creating a non-uniform doping concentration distribution within the doped portion of the active layer. Specifically, the doping concentration is designed to be higher near the drain electrode and lower near the source electrode, forming a gradient structure. This local variation in doping concentration allows different regions of the same component to serve different functions: the high-doping region near the drain reduces voltage drop and self-heating, while the low-doping region near the source maintains high carrier mobility for performance.

Inventive Principle:
Principle #3Local quality

2Loss of energy

If doping concentration is increased to reduce resistance, then voltage drop decreases, but self-heating increases causing stability issues

Engineering Contradiction:
Improvevoltage dropVSAvoidself-heating
Core Design Contradiction:
Loss of energyVSTemperature

Solution Approach 1:

The patent applies local quality by creating a non-uniform doping concentration distribution within the doped portion of the active layer. Specifically, the doping concentration is designed to be higher near the drain electrode and lower near the source electrode, forming a gradient structure. This local variation in doping concentration allows different regions of the same component to serve different functions: the high-doping region near the drain reduces voltage drop and self-heating, while the low-doping region near the source maintains high carrier mobility for performance.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If uniform doping concentration is used in doped portions, then manufacturing is simplified, but performance and stability cannot be simultaneously optimized

Engineering Contradiction:
Improvedoping process simplicityVSAvoidtransistor stability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies local quality by creating a non-uniform doping concentration distribution within the doped portion of the active layer. Specifically, the doping concentration is designed to be higher near the drain electrode and lower near the source electrode, forming a gradient structure. This local variation in doping concentration allows different regions of the same component to serve different functions: the high-doping region near the drain reduces voltage drop and self-heating, while the low-doping region near the source maintains high carrier mobility for performance.

Inventive Principle:
Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The design enhances the stability of transistors by reducing voltage drop and connection impedance, improving performance stability while maintaining high mobility.

Implementation Method 1

the resistance of the second doped sub-portion is greater than that of the first doped sub-portion, thereby reducing the voltage drop of the first doped portion connected to the drain, and improving the problem of poor stability of the first transistor due to self-heating

Methodology Applied
Scientific EffectElectrical Resistance: Electrical Resistance

Data Source

PatentEP4489074A1Array substrate and display panel
Publication Date: 2025.01.08 SHENZHEN CHINA STAR OPTOELECTRONICS SEMICON DISPLAY TECH CO LTD
  • EP4489074A1 patent drawingFigure 1A~1D
  • EP4489074A1 patent drawingFigure 1E~1G
  • EP4489074A1 patent drawingFigure 1H~2

AI summary

An array substrate (10) includes a substrate (101) and a first transistor (T1) disposed thereon. The first transistor (T1) includes a first active layer (103), a first channel portion (1031), a first doped portion (1032), a second doped portion (1033), a first gate (105), a source (1081) and a drain (1082). The first doped portion (1032) and the second doped portion (1033) are connected to opposite ends of the first channel portion (1031), respectively. The first doped portion (1032) includes a first doped sub-portion (10321) and a second doped sub-portion (10322) connected between the first channel portion (1031) and the first doped sub-portion (10321). A doping concentration of ions in the second doped sub-portion (10322) is less than that in the first doped sub-portion (10321), and a doping concentration of ions in the first doped sub-portion (10321) is the same as that in the second doped portion (1033).